Condenser leakage monitoring system

ABSTRACT

A condenser leakage monitoring system for power plants including individual sampling path derived from each divided section of the condenser and a sealed cycle provided within a vacuum zone for recirculation of the sample after inspection. The sampling path is connected to an inlet valve which is in turn connected to a sealed or canned motor pump and the canned motor pump is further connected to the conductivity measuring cell which is electrically connected to a conductivity meter and also communicated to an outlet valve through a detecting electrode.

United States Patent Hotta et al.

[ Oct. 24, 1972 [54] CONDENSER LEAKAGE MONITORING SYSTEM [72] Inventors:Takeshi Hotta; Hisashige lshikawa, both of c/o Nikkiso Co., Ltd. No.43-2, Ebisu 3-chome, Shibuya-ku, Tokyo, Japan [22] Filed: Feb. 17, 197121 Appl.No.: 116,024

[52] US. Cl. ..73/40.5 R, 176/19 LD [51] Int. Cl. ..G0lm 3/18, GOlm 3/22[58] Field of Search..73/40, 405 R, 53, 61 R, 61.1 R,

[56] References Cited UNITED STATES PATENTS 3,395,074 7/1968 Douet et al..176/19 LD Primary Examiner-Louis R. Prince Attorney-Young & Thompson[57] ABSTRACT A condenser leakage monitoring system for power plantsincluding individual sampling path derived from each divided section ofthe condenser and a sealed cycle provided within a vacuum zone forrecirculation of the sample after inspection. The sampling path isconnected to an inlet valve which is in turn connected to a sealed orcanned motor pump and the canned motor pump is further connected to theconductivity measuring cell which is electrically connected to aconductivity meter and also communicated to an outlet valve through adetecting electrode.

2 Claims, 2 Drawing Figures Go Go Game PATENTEDUET24 m2 INVENTOR TAKESHIHOTTA H ISASHIGE ISHIKAWA 7 7 ATTORNEYS CONDENSER LEAKAGE MONITORINGSYSTEM I BACKGROUND OF THE INVENTION The present invention relates topower plant water conditioning system and, more particularly, tocondenser leakage monitoring system of the type wherein individualsampling path is derived from each desired parts of the condenser toinspect deterioration degree of the condensate providing a sealed cyclewithin a vacuum zone for recirculation of samples.

Generally in the power plants, inter alia,the nuclear power plant,majority of water supply is carried out by reuse of condensate whichshould always be conditioned pure. That is, the condensate must beprotected from suffering deterioration for example due to inflow ofcooling water such as sea water.

The inventors have developed an improved condenser leakage monitoringsystem for the thermal power plant wherein any generation and degree ofleak of sea water are accurately detected by measurement of conductivityin such a way that a sealed cycle of the sample with a perfectly seal-edor canned motor pump is connected to individual section of the condenserfor sampling to inspect the deteriorated section of the condenser moreaccurately.

It has been appreciated that the above developed condenser leakagemonitoring system may be effectively applicable to the condenser in thenuclear power plant. However, in the nuclear power plants, particularly,of the types such as enriched uranium reactor, water cooled reactor,water moderated reactor and boiling water reactor, the condensate has apossibility of suffering radioactive contamination which makes theoperation as well as maintenance of the aforementioned monitoring systeminconvenient.

In the nuclear power plant, the sampling region should be positionedpossibly apart from the reactor to avoid radioactive influence, whilethe sealed or canned motor pump for sampling must be positioned possiblynear the condenser on account of its characteristic such as the netpositive suction head (NPSH). If, however, the canned motor pump ispositioned near the condenser, the operator can not approach to inspectthe motor pump when the accident arises due to radioactive influence orthe necessity arises of repairing the pump due to abrasion of thebearing.

SUMMARY OF THE INVENTION A general object of the invention is to obviatethe above disadvantages and difficulties and to provide an improvedcondenser leakage monitoring system for power plants in which the sealedor canned motor pump is positioned near the condenser free from anyrepair for a certain period.

A further object is to provide a condenser leakage monitoring system forpower plants which comprises individual sampling path derived from eachdivided section of the condenser and a sealed cycle provided within avacuum zone for recirculation of the sample after inspection.

In accordance with the present invention, individual sampling path isderived from each divided section of the condenser and connected to aninlet valve which is in turn connected to a sealed or canned motor pumpproviding a sealed cycle of the sample. The canned motor pump is thenconnected to the conductivity measuring cell which is electricallyconnected to a conductivity meter and also communicated to an outletvalve through a detecting electrode.

Another object is to provide a condenser leakage monitoring system forpower plants comprising individual sampling path derived from eachdivided section of the condenser and a sealed cycle provided within avacuum zone for recirculation of the sample after inspection, whereinsaid individual sampling path is connected in series to a circuitcomprising an inlet valve, a canned motor pump and an outlet valve, saidcircuit being further connected in parallel to one or more additionalcircuits comprising an inlet valve, a canned motor pump and an outletvalve, providing a circuit for switching valve and starting or stoppingthe canned motor pump through a relay means in accordance with thepredetermined operation period or tolerable limit of the bearingabrasion thereby automatically switching the canned motor pump in order.

Other objects and advantages of the present invention will becomeapparent from a consideration of the following detailed descriptiontaken in connection with the accompanying drawings wherein asatisfactory embodiment of the invention is shown. However, it willbeunderstood that the invention is not limited to the details disclosedbut includes all such variations and modifications as fall within thespirit of the invention and the scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS:

In the drawings:

FIG. 1 is a diagrammatical view of the condenser leakage monitoringsystem in accordance with the invention; and

FIG. 2 is a diagrammatical view of the condenser leakage monitoringsystem of another embodiment.

DESCRIPTION OF THE PREFERRED Y EMBODIMENT:

In an embodiment shown in FIG. 1, the reference numeral 10 designates acondenser from the desired sections of which individual sampling path 12is derived. The sampling path 12 is connected to an inlet valve 14 whichis in turn connected in series from a strainer 16 through a cationexchange column 18 to a vacuum nonleak canned motor pump 20. The cannedmotor pump 20 is further connected to a conductivity measuring cell 22which is electrically connected to a conductivity meter 24 andcommunicated through a flow gage 26 and a strainer 27 to an outlet valve28 for recirculation of the sample thereby providing a sealed cycle ofthe sample within a vacuum zone. When the deterioration of the sample isto be inspected, removal or demineralization of the deteriorated waterin the condenser is carried out automatically by an actuation of therelay.

In another embodiment shown in FIG. 2, individual sampling path 12 isderived from each divided section of the condenser 10 and then connectedto a sealed cycle of the sample for recirculation as illustrated inconnection with the embodiment shown in FIG. 1.

The sample flows passing through the inlet valve 14, a canned motor pump20 and an outlet valve 30 into a measuring section 32 wherein the sampleis permeated through a cation resin mass 34 to substitute a small amountof salt contained in the condensate thereby amplifying the conductivity.

The sample further flows through a flow meter 36 and an electrode 38wherein an electrolytic conductivity is measured to detect thedeterioration of the condensate and the sample is finally refluxedthrough valves 40 and 42 into the condenser 10.

The measuring section 32 is positioned apart from the condenser 10,while the canned motor pump is positioned near the condenser 10. Thecanned motor pump 20 provides an impeller in the same shaft as the rotorand said common shaft is carried by the hearing which usually reachesthe tolerable limit after about 5,000 to 8,000 hours. When the bearinglife comes to cessation, the operation should be stopped immediately.Accordingly, the necessity arises of operating another additional pumpuntil the next periodical inspection of the first pump.

In accordance with the present invention, two or more circuitscomprising the inlet valve, the sealed pump and the outlet pump areconnected selectively in parallel.

ln starting the operation, a starting switch 44 is put on to open inletand outlet solenoid valves 14 and 30 while closing simultaneously alimit switch contact for indication of the valve opening. Further, arelay of control box 46 is actuated to close a pump relay contactthereby starting the pump while energizing simultaneously a time-setintegrating meter (not shown) through the relay to integrate theoperation period of the pump and to detect the bearing abrasion by meansof an abrasion detector (not shown) providing the tolerable limit of thebearing.

When the predetermined operation period passed or the bearing abrasiongets over a certain tolerable limit, a signal is brought to stop theoperation of the pump 20 and to close the valves 14 and 30 while openingsimultaneously the valves 14a and 30a to start the pump 20a thusswitching into another pump circuit. In this way, the pump circuit maybe switched successively in accordance with the bearing abrasion untilthe next periodical inspection of the pump.

According to the invention, the pump on operation may be switchedinstantaneously without necessitating any artificial repair ormaintenance by the operator within a certain period.

We claim:

1. A condenser-leakage monitoring system for power plants whichcomprises an individual sampling path derived from each divided sectionof the condenser and a sealed cycle formed within a vacuum zone forrecirculation of the sample after inspection, said individual samplingpath being derived from each divided section of the condenser andconnected to an inlet valve which is in turn connected to a canned motorpump which is further connected to a conductivity measuring cell, saidconductivity measuring cell including a detecting electrode and furtherbeing electrically connected to a conductivity meter and also through anoutlet valve back into the respective section of the condenser.

2. A condenser-leakage monitoring system for power plants whichcomprises an individual sampling path derived from each divided sectionof the condenser and a sealed cycle formed within a vacuum zone forrecirculation of the sample after inspection, said indiyidual samplingpath being connected in senes to a fluld circuit comprising an inletvalve, a canned motor pump, a testing cell and an outlet valve, saidcircuit being further connected in parallel to at least one additionalfluid circuit comprising an inlet valve, a canned motor pump, a testingcell and an outlet valve, electrical circuit means for opening andclosing said valves and for starting and stopping the canned motor pumpin each fluid circuit, and means responsive to a predetermined operationperiod or tolerable limit of the bearing abrasion of the canned motorpump in the first-mentioned fluid circuit for automatically closing thevalves in the first mentioned fluid circuit and stopping the motortherein and for opening the valves and starting the motor in saidadditional fluid circuit.

1. A condenser-leakage monitoring system for power plants whichcomprises an individual sampling path derived from each divided sectionof the condenser and a sealed cycle formed within a vacuum zone forrecirculation of the sample after inspection, said individual samplingpath being derived from each divided section of the condenser andconnected to an inlet valve which is in turn connected to a canned motorpump which is further connected to a conductivity measuring cell, saidconductivity measuring cell including a detecting electrode and furtherbeing electrically connected to a conductivity meter and also through anoutlet valve back into the respective section of the condenser.
 2. Acondenser-leakage monitoring system for power plants which comprises anindividual sampling path derived from each divided section of thecondenser and a sealed cycle formed within a vacuum zone forrecirculation of the sample after inspection, said individual samplingpath being connected in series to a fluid circuit comprising an inletvalve, a canned motor pump, a testing cell and an outlet valve, saidcircuit being further connected in parallel to at least one additionalfluid circuit comprising an inlet valve, a canned motor pump, a testingcell and an outlet valve, electrical circuit means for opening andclosing said valves and for starting and stopping the canned motor pumpin each fluid circuit, and means responsive to a predetermined operationperiod or tolerable limit of the bearing abrasion of the canned motorpump in the first-mentioned fluid circuit for automatically closing thevalves in the first mentioned fluid circuit and stopping the motortherein and for opening the valves and starting the motor in saidadditional fluid circuit.